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Mapping quantitative trait loci underlying genome-wide recombination rate and mating system differences in meadowfoamKishore, Venkata Krishna 21 March 2002 (has links)
Meadowfoam (Limnanthes alba Bentham; Order: Brassicales; Family:
Limnanthaceae) is a self-compatible, predominantly allogamous, insect pollinated
species. Meadowfoam oil is a source of novel unsaturated very-long-chain (VLC) seed
oils (C������ and C������) with low concentrations of saturated fatty acids (typically less than
2%) and outstanding oxidative stability. Here we report the development of 389 SSR
markers for meadowfoam. All the 389 SSRs were screened on 14 meadowfoam
germplasm accessions to assess their utility and efficiency. Ninety-six percent of the
SSR markers (373 out of 389) were polymorphic among the 14-germplasm accessions
(from nine taxa) with a mean heterozygosity of 0.63.
We also report that the physical size of the meadowfoam genome was
estimated to be 5.52 pg using flow cytometry; thus, the meadowfoam genome is ca. 16
times larger than the Arabidopsis genome. Karyotype analyses revealed that the
meadowfoam genome is made up of two metacentric and three submetacentric
chromosomes. Meadowfoam has two pairs of chromosomes with subterminal
nucleolar organizing regions (NOR's). A genetic map comprised of 84 SSR loci
dispersed among five linkage groups with 11 to 22 SSR loci per linkage (6 SSR loci
segregated independently) was constructed. The map was 988.7 cM long with a mean
density of 11.8 cM and minimal clustering of loci.
A total of 20 quantitative trait loci (QTL) were identified for five mating
system characters in meadowfoam, using the SSR linkage map of meadowfoam.
Individual QTL for mating system traits peta1 area (pa), seeds per plant (spp) and
seeds per flower (spf)I account for up to 20% of the backcross phenotypic variance,
with most traits showing QTL effects of 5-15%. The QTL for protandry and chiasma
frequency were adjacent to the QTL for spp and spf. This study has provided evidence
that the correlation between the chiasma frequency and the type of mating system is
not a direct developmental relationship between these factors, but is due to a selective
advantage of the combination of the characters found. The speculation that the genetic
factors underlying chiasma frequency and autonomous seed set have co-evolved
during evolution negates the self-fertilization as an "evolutionary dead end". / Graduation date: 2002
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Somatic hydridisation within the genus BrassicaLoudon, Peter T. January 1989 (has links)
No description available.
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Characterisation of storage lipid accumulation in developing fruits and cell cultures of corianderBowra, Steve January 1998 (has links)
No description available.
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Genetic variation in Pyrenopeziza brassicae and its interaction with its host Brassica napus ssp. oleiferaMajer, Dorothea January 1997 (has links)
No description available.
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Genome structure and genetic diversity in Crambe L. BrassicaceaeFord, Kate E. January 2000 (has links)
No description available.
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Seasonal and allergic symptoms in rural populationsSoutar, Anne J. January 1995 (has links)
Asthma and hayfever are common diseases in children and adults. There have been dramatic increases in the prevalence of allergic diseases over the last 25 years. Either the environment has become more toxic or the population more susceptible. Concern has been expressed that cultivation of oilseed rape leads to seasonal epidemics of respiratory symptoms in populations living near the crop. In order to investigate this apparently widespread problem a combined epidemiological and environmental study was carried out. A cross sectional study was conducted to determine the prevalence of symptoms in a rape growing area compared with a non-rape area. Detailed environmental sampling and a small case-control study to investigate atopy and bronchial reactivity were also conducted. There have been dramatic changes in the Western diet over the last 30 years, with the diet including progressively less fresh food containing antioxidants. It is possible that these changes have increased the susceptibility of the populations to potentially harmful substances. A case-control study was conducted to test the hypothesis that a diet low in antioxidants is a factor in the expression of allergic diseases. Seasonal symptoms were found to be widespread in both rape growing and non-rape growing areas, with only a very small excess of seasonal symptoms occurring in rape growing areas. Little evidence of allergy to oilseed rape, which is consistent with the low levels of pollen recorded, was found. However, there was an increase in bronchial reactivity during the flowering season, especially among cases. This could be a result of non-specific irritation due to terpenes released from the crop.
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The characterisation of barley and wheat oxalate oxidases expressed in transgenic plantsIlett, Colin John January 1998 (has links)
Oxalate oxidase is a water soluble, thermolabile, homo-oligomeric glycoprotein the synthesis of which marks the onset of germination In wheat and barley embryos. The protein Is also highly abundant In barley roots. The enzyme has an average oligomer molecular mass of about 115 kDa and about 22.8 kDa for the monomers, as determined by mass spectrometry. The ollgomeric cereal oxalate oxidases are resistant to dissociation In SDS containing media and to digestion by pepsin. The cereal organs produce two oxalate oxidase Isoforms (G and G') which possess the same apoprotein but are differentially glycosylated. The oligosaccharide side chain(s) has a molecular mass of about 2-3 kDa. Barley root also contains a third active oxalate oxidase isoform with a mass of about 22.5 kDa, which was not detected in germinating embryos of the same cultlvar. All of the cereal oxalate oxidases were shown to have identical N-terminal amino acid sequences and almost identical kinetic properties This thesis describes the characterisation of oxalate oxidases Isolated from three transgenic plants lines, expressing chimeric CaMV 35S-oxalate oxidase genes. SGS5 tobacco was expressing a gene with the native oxalate oxidase signal peptide and 3S1 oilseed rape and C26 tobacco were expressing a gene containing a foreign extensin signal peptide. Transgenic SGS5 tobacco produced an oxalate oxidase which was almost indistinguishable from the native cereal protein, in terms of Its structure, stability, enzyme activity and resistance to dissociation In SDS containing media and digestion by pepsin. This work Illustrated the ability of a dicotyledonous plant (tobacco) to recognised and correctly process a transgenic monocotyledon protein (wheat).Transgenic 3S1 oilseed rape and C26 tobacco were shown to produce active oligomeric oxalate oxidases, which did not exhibit any of the unusual resistance properties normally associated with these proteins. Instead the 3S1 and C26 oxalate oxidases were unstable and exhibited significantly altered kinetic properties compared with the native cereal and transgenic SGS5 enzymes. The instability was thought to have arisen from the Incorrect processing of the 3S1 and C26 oxalate oxidases, resulting in the partial cleavage of the extensin signal peptide, which in turn gave rise to a mature oxalate oxidase with an altered N- terminal sequence compared with the native cereal enzyme. The use of vacuum infiltration confirmed the association of the transgenic enzymes with the extracellular spaces, although the majority of the enzyme was shown to be intracellular. The main objective for producing the transgenic oilseed rape expressing oxalate oxidase was to Improve fungal pathogen resistance against oxalic acid secreting pathogens. The results described in this thesis are concerned with a direct comparison of the structure, stability and kinetics between the native cereal and transgenic oxalate oxidases and the possible consequences for pathogen resistance In plants expressing unstable yet active transgenic enzymes.
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Chemical characterization of camelina seed oilSampath, Anusha, January 2009 (has links)
Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Food Science." Includes bibliographical references (p. 165-170).
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In vivo regulatory phosphorylation of bacterial-type phosphoenolpyruvate carboxylase from developing castor oil seedsO'LEARY, BRENDAN MICHAEL 07 September 2011 (has links)
PEPC [PEP(phosphoenolpyruvate) carboxylase] is an essential and tightly controlled enzyme located at the core of plant C-metabolism. It fulfils a broad spectrum of non-photosynthetic functions, particularly the anaplerotic replenishment of tricarboxylic acid cycle intermediates consumed during biosynthesis and N-assimilation. In plants, a small multigene family encodes several closely related plant-type PEPC (PTPC) isozymes along with a distantly related bacterial-type PEPC (BTPC) isozyme. The PTPCs are well studied ~110-kDa subunits that typically exist as a homotetramer (Class-1 PEPC). By contrast, little is known about the larger ~118-kDa BTPC isozyme except that it occurs in developing castor (Ricinus communis) endosperm in tight association with PTPC subunits as a ~900-kDa hetero-octameric complex (Class-2 PEPC) that is greatly desensitized to metabolic effectors compared to Class-1 PEPC. This thesis elucidates the physiological purpose of the BTPC subunits by examining their structure/function relationship within Class-2 PEPC and identifying mechanisms of post-translational control. Recombinant expression and purification of the castor bean BTPC revealed unusual physical and kinetic properties including a remarkable insensitivity to metabolic effectors and a dependence upon PTPC subunits for structural stability. The first purification of a non-proteolyzed plant Class-2 PEPC complex was performed, and the kinetic analysis determined that the BTPC and PTPC subunits have complimentary catalytic properties. The BTPC subunits’ high Km(PEP) and desensitization to metabolic effectors may function as a metabolic overflow mechanism for sustaining flux from PEP to malate when PTPC subunits become feedback inhibited. An anti-PTPC co-immunopurification strategy was utilized to highly enrich non-proteolyzed BTPC from developing castor endosperm for downstream immunological and mass spectrometric analysis. BTPC was in vivo phosphorylated at multiple novel sites, identified by mass spectrometry as Thr4 or 5, Ser425 and Ser451. Phosphosite-specific antibodies towards Ser425 and Ser451 confirmed the existence of these sites in vivo and comparisons of Ser425 phosphorylation patterns established that the castor BTPC and PTPC phosphorytation sites are regulated independently. Phosphomimetic mutants of Ser425 caused BTPC inhibition by increasing its Km(PEP) and sensitivity to feedback inhibition. These results establish a novel mechanism of PEPC control whose implications within plant carbon metabolism are discussed. / Thesis (Ph.D, Biology) -- Queen's University, 2011-09-04 16:46:22.024
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Genetic analysis of Sinapis albaNelson, Matthew N. January 2000 (has links)
No description available.
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